Napa Valley is approximately 35 miles long and one to five miles wide. It’s snug between the Mayacamas and Vaca mountains in northern California and claims some of the most expensive agricultural land in the world. The convergence of the right soils, climate, elevation, and skills of the grape grower and winemaker, make Napa Valley one of the most revered wine appellations in North American.
Napa Valley is itself an appellation and has 16 unique sub Appellations (AVA’s) within its boundaries. Each AVA has a distinctive microclimate, soil, terrain, and elevation that imprint their identifiable characteristics on their fruit. Matching the right grape variety, root stock, trellis system, vine spacing, irrigation, nutrient amendments, cover crops and wine making style to the vineyard location, contributes to the unique “terroir” of the vineyard.
Here are overviews of the region’s American Viticultural Appellations (AVA) starting from the cooler southern part of the valley.
Los Carneros AVA – The Rams. Spanning Napa and Sonoma counties this is the coolest grape growing region in the area with just over 1,000 acres planted. This rural area at the base of the valley has no small towns, restaurants or shops. There are over a dozen wineries here, including a number making sparkling wines, and most have tasting facilities. Call for appointments.
The prevailing marine winds from San Pablo Bay keep the summertime high temperatures under 80 degrees. Cool and wind-whipped, the AVA has thin soils and only 18 to 23 inches of rain annually. With shallow soils dominated by clay yields are generally low. The principle white grape is Chardonnay which often displays crisp, mineral flavors of pear-apple, lemon, pineapple and spice. The dominate red wine grape Pinot Noir, is known for its tight structure, its earthy, ripe cherry-cinnamon and spicy berry flavors.
Mt. Veeder is a small, 25-square-mile appellation located on the western slopes of the Mayacamas Mountains in the southern part of the valley. Most of the 1,000 acres of vineyards are above the fog line allowing for warmer nights and cooler days. Some of the most remote wineries and steepest vineyards are found here on this rugged, volcanic mountain producing intense chewy red wines with firm tannic structure, distinctive earth and berry aromas and a bit of spice. The white wines have a minerally character and even some notes of citrus and apples. Less than a dozen wineries hide out in this remote area.
Oak Knoll District– Just north of Carneros is the slightly warmer area of Oak Knoll with 3,500 acres under vine. Located at the southern end of the Napa Valley it has a relatively low elevation ranging from sea level to about 800 feet. Soils in the northeast are volcanically derived with a gravelly consistency. In the south, soils transition from to silty clay to loam.
The cool air from San Pablo Bay creates conditions where temperatures rarely reach over 90 degrees. Rainfall is moderate averaging 36 inches annually. The area has a dozen wineries with tasting rooms, with many more purchasing fruit from the region.
Wines from Oak Knoll are known for an elegant restrained style with fruit flavors of cassis, tobacco and spice. Merlot Chardonnay and Cabernet Sauvignon are the principle varieties as well as Riesling.
Destination Winery in Yountville
Yountville has a moderate climate with the marine influence keeping temperatures generally under 90 degrees in the summer. Temperatures will drop 30 to 40 degrees in the evenings. Soils are sedimentary and moderately fertile. Rainfall averages 32 inches. The Cabernet Sauvignon and Merlot grown here are known for their rich supple flavors and firm tannins. The small town has shopping, and a number of hotels, inns, and places to eat.
Stags Leap District was the first viticultural area in the United States to be approved based on the distinctiveness of its river sediments and volcanic mountain soils. Located five miles north of the town of Napa along the Silverado Trail the region is a mile wide and two miles long. 1,400 acres are planted mostly to Cabernet Sauvignon, Sangiovese and Merlot. The wines are powerful and distinguished by their lush, velvety textures, cherry and berry flavors and their soft tannins. Stags Leap is heavily influenced by the cool breezes and give the district an exceptionally long growing season. The district is moderately warm reaching 100 degrees in mid-summer. Rainfall is 30 inches annually and elevations range from 66 to 400 feet. The district is home to 16 wineries.
Atlas Peak faces west from the eastern side of the valley near the city of Napa, and has the benefit of direct afternoon sunlight. The 11,000 acre area is 10 to 15 degrees cooler than the Valley floor in the summer with temperatures rarely above 90 degrees. Elevations run from 1100 to 1800 feet with rainfall averaging 35 inches annually. The red basaltic soils are porous requiring irrigation on most of the regions 1500 acres of vines. Zinfandel, Cabernet Sauvignon, Sangiovese and Chardonnay are planted producing wines with good acidity and bright fruity flavors for the reds and flora, aromatic and pear flavors for the whites. A dozen wineries can be found here with most requiring an appointment for tasting.
Wild Horse Valley AVA, is a mere 3,300 acres in size with only one winery and three vineyards that total about 110 acres. Straddling Napa and Solano counties this area is warmer and well to the east of Napa Valley proper. Its southerly location at elevations of 400 to 1,500 feet exposes it to cool westerly winds from the ocean and bay. 35 inches of rain fall annually on its shallow volcanic soils. Cabernet Sauvignon and Sangiovese are the principle red grapes with characteristics of cherries and berries. The Chardonnay has distinctive aromatic flavors of pears and floral notes with good acidity.
Oakville lies in the flat open spaces of Napa Valley with over 5,000 acres of vineyards carpeting the valley floor. The deep gravelly and sandy clay loam soils are a perfect match for Bordeaux varietals. Thirty-six wineries reside here with many being the most historic and prestigious. Cabernet and Merlot are grown and have a rich texture, firm tannins, and ripe currant, herb and mint flavors. The temperatures can reach the mid-90’s in the summer then cooling with morning and evening fog.
Entry at Rubicon Estate, Rutherford California
Rutherford is just north of Oakville and has a population of close to 600 in its six square miles. Located at the valley’s widest point, Rutherford’s 3,263 acres of vineyards receive more sun than most other areas with mid-summer temperatures reaching the mid 90’s. Soils are well drained and primarily gravel, sand and loam, with more volcanic deposits found on its eastern side. Rainfall averages 38 inches a year. Cabernet Sauvignon is king here with 70% of the vineyards planted to the variety with Merlot, Sauvignon Blanc, Chardonnay and Cabernet Franc rounding out the top five. Characteristics of the region include the dusty, berry, allspice and light herbaceous. Some wines exhibit intense cherry, currant and earthy flavors. Supple tannins are common allowing for longer aging.
St. Helena is the cultural, social and economic heart of the Napa Valley covering just over 9,000 acres with less than 1,000 acres of vineyards. Located where the Napa Valley floor narrows, this region is considered the center of Napa viticulture with 30 wineries located here. Cabernet Sauvignon, Zinfandel and Merlot represent 70% of the grape varieties grown in the region. Cool Pacific breezes from the north cool the vines which can create 40 degree temperature swings from day to night. Soils are sedimentary, gravel-clay with low fertility and moderate water retention. Rainfall averages 38 to 40 inches a year. Wines here are graceful, with concentrated fruit flavors, often jammy, with firm tannins and aromas of currant, blackberry and cherry.
Sycamore Trees at Peju Province Winery
Spring Mountain grapes are handpicked from steep terraces of the Mayacamas Mountains. Just west of St Helena the vineyards here are small and reside at elevations ranging from 400 to 2,100 feet. Days are cooler and nights are warmer than on the valley floor, allowing for a longer growing season. Up to 50 inches of rain fall during the year on the well drained, weathered sandstone and shale soils. The red wines are powerful with blackberry-currant flavors with good acidity, richly tannic and generally not as fruity as those found at lower elevations.
Howell Mountain overlooks St. Helena from the Vaca Range on the Valley’s northeast side and encompasses around 14,000 acres with only 600 acres of vines. Vineyards can be found at elevations ranging from 600 to 2,200 feet on this rugged mountain above the fog line. Up to 50 inches of rain fall on the shallow, infertile volcanic soils. Cabernet Sauvignon, Merlot, and Zinfandel have rich powerful black-berry and currant flavors with robust tannins for aging. The Chardonnays are less fruity and have more stone fruit and citrus flavors.
Chiles Valley is a narrow appellation in the Vaca Mountains along the northeast side of the Napa Valley and covers an area of approximately 6,000 acres, with more than 1,000 acres under vine. Warm summers and cool evenings make for a long growing season for the Zinfandel, Cabernet Sauvignon, Merlot, Chardonnay and Sauvignon Blanc that are grown here. Cooling maritime breezes rarely reach this far east. The valley floor has primarily alluvial soils while the hillsides have more clay-loam and stony-clay composition. The red wines exhibit lush yet firm textures with distinctive cherry and blackberry flavors.
Diamond Mountain District is a tiny appellation that covers 5,000 acres on the northeastern side of the Mayacamas Mountain range with only about 500 acres planted to grapes. Cabernet Sauvignon and Cabernet Franc reign supreme here in this rocky outpost creating firmly structured, rich, chewy wines with plenty of tannin for aging. The reds will often have mineral flavors of black currant and cedar. The Chardonnays are full bodied with firm acidity and green apple aromas.
Coombsville is a quiet area, in the southeastern corner of the Napa Valley, tucked up against the foothills of the Vacas Range, just outside of historic Napa town. Coombsville become an official Napa Appellation in December 2011. Coombsville vintners production mirrors that of Napa Valley, with a focus on Cabernet Sauvignon and other French varietals. Due to its varied soil types and the numerous meso-climates spread throughout its rolling landscape, excellent examples of Syrah, Chardonnay, and Pinot Noir are also produced. For more info see Coombsville Vintners & Growers